Package g1901_2000.s1987_number_of_unique_good_subsequences

Class Solution

java.lang.Object
g1901_2000.s1987_number_of_unique_good_subsequences.Solution
public class Solution extends Object
1987 - Number of Unique Good Subsequences\. Hard You are given a binary string `binary`. A **subsequence** of `binary` is considered **good** if it is **not empty** and has **no leading zeros** (with the exception of `"0"`). Find the number of **unique good subsequences** of `binary`. * For example, if `binary = "001"`, then all the **good** subsequences are `["0", "0", "1"]`, so the **unique** good subsequences are `"0"` and `"1"`. Note that subsequences `"00"`, `"01"`, and `"001"` are not good because they have leading zeros. Return _the number of **unique good subsequences** of_ `binary`. Since the answer may be very large, return it **modulo** 109 + 7. A **subsequence** is a sequence that can be derived from another sequence by deleting some or no elements without changing the order of the remaining elements. **Example 1:** **Input:** binary = "001" **Output:** 2 **Explanation:** The good subsequences of binary are ["0", "0", "1"]. The unique good subsequences are "0" and "1". **Example 2:** **Input:** binary = "11" **Output:** 2 **Explanation:** The good subsequences of binary are ["1", "1", "11"]. The unique good subsequences are "1" and "11". **Example 3:** **Input:** binary = "101" **Output:** 5 **Explanation:** The good subsequences of binary are ["1", "0", "1", "10", "11", "101"]. The unique good subsequences are "0", "1", "10", "11", and "101". **Constraints:** * 1 <= binary.length <= 105 * `binary` consists of only `'0'`s and `'1'`s.

  • Constructor Details

    • Solution

      public Solution()

  • Method Details

    • numberOfUniqueGoodSubsequences

      public int numberOfUniqueGoodSubsequences(String binary)